1. Field of the Invention
The invention relates to technology for adjusting the temperature inside a battery case.
2. Description of Related Art
In recent years, electric vehicles and hybrid vehicles and the like that have an electric motor for running the vehicle are receiving a lot of attention as environmentally friendly vehicles and have come to be put into practical use. The electric motor is driven by electric power output from a battery that has a plurality of single cells capable of charging and discharging.
In a high temperature environment, the battery will deteriorate faster, so the life of the battery will be shorter. Therefore, various countermeasures against heat are being implemented.
Japanese Patent Application Publication No. 2005-093434 (JP 2005-093434 A) describes a system that cools the inside of a battery case. In this cooling system, when the temperature inside the battery chamber is higher than the temperature outside the vehicle, air from outside the vehicle is introduced into the battery case by driving a fan. When the temperature outside the vehicle is higher than the temperature inside the battery case, the air that is drawn in by driving the fan is introduced into the battery case after first being cooled by being passed through an evaporator coil.
However, in JP 2005-093434 A, the fan must be driven in order to cool the battery, so the amount of energy consumed increases. When the temperature outside the vehicle is higher than the temperature inside the battery case, that air must be cooled using air-conditioning refrigerant. Therefore, it is not possible to suppress an increase in the temperature of the battery while the vehicle is stopped.